Self-monitoring of water quality in sewer systems using absorbance of ultraviolet and visible light

2001 ◽  
Vol 44 (2-3) ◽  
pp. 269-276 ◽  
Author(s):  
G. Ruban ◽  
Y. Yuperd ◽  
B. Laveau ◽  
E. Lucas
Keyword(s):  
Optical Measurement ◽  
Oxygen Demand ◽  
Feeding System ◽  
Short Delay ◽  
Self Monitoring ◽  
Line Measurement ◽  
Rainy Weather ◽  
On Line ◽  
Pollution Measurement

Continuous pollution measurement is interesting to optimize the operation of sanitary facilities as well as to minimize the stormwater discharges. An experimental study was carried out for the determination of Suspended Solids (SS) and Chemical Oxygen Demand (COD) concentrations in combined sewers using ultraviolet and visible absorbances. The maintenance of the measurement system requires six hours a month for the cleaning of the hydraulic feeding system and adjustment of the optical device. The feeding system developed increased the representativeness and reliability of the pollution measurement, but needs to be validated on other measurement sites. The determination of SS concentrations from visible absorbances requires 2 calibration curves for dry and rainy weather respectively. The corresponding accuracies appear satisfactory when compared with the results of standard sampling/laboratory analysis. The accuracy of COD determination from ultraviolet absorbance is less satisfactory, but could perhaps be improved taking into account another parameter. Then the optical measurement of SS and COD is interesting to determine average or long term pollution loads, for example the yearly impact of urban stormwater discharges. With this kind of continuous and on-line measurement, it is possible to react with short delay to unexpected phenomena which could damage the environment or water treatment efficiency.

New developments of computer-aided crystallographic analysis in transmission electron microscopy

2000 ◽  
Vol 33 (1) ◽  
pp. 10-25 ◽  
Author(s):  
Stefan Zaefferer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallographic Analysis ◽  
Foil Thickness ◽  
Orientation Measurement ◽  
Transmission Electron ◽  
Line Measurement ◽  
On Line ◽  
Diffraction Patterns

A new computer program for on-line crystallographic analysis in transmission electron microscopy (TEM) is presented. The program is based on the fast on-line determination of single-crystal orientations from Kikuchi and spot patterns. Spot patterns, which are particularly useful in the case of highly deformed metals, are analyzed by a new digital image processing procedure. This procedure improves the precision and ease of the orientation measurement. The program permits the on-line measurement of glide systems characterized by the Burgers vector and the crystallographic line direction of dislocations and their glide planes. The determination of twin systems, based on the misorientation calculation for any crystal structure, is included as well. The possibility of determining the foil thickness permits the complete crystallographic characterization of interfaces. Finally, the program facilitates the discrimination of phases and includes the fit of the lattice parametersa,bandcfrom diffraction patterns. The new procedures are described in detail. Application examples are given for all functions.

scholarly journals The Assessment of Cross Machine Openness Uniformity of a Fiber Feed Matt

2000 ◽  
Vol os-9 (4) ◽  
pp. 1558925000OS-90
Author(s):  
Ayad Oumera ◽  
Abdelfattah M. Seyam ◽  
William Oxenham
Keyword(s):  
Thickness Measurement ◽  
One Dimensional ◽  
Line Measurement ◽  
On Line ◽  
Compression Data ◽  
The One ◽  
Compression Characteristics ◽  
Input Level

The one-dimensional characteristic of yarn has resulted in very little attention being given to the uniformity of carded web in the cross machine direction. The development of nonwovens has prompted researchers to reconsider the importance of cross machine uniformity in determining the total uniformity of the carded web. It is therefore important to develop manual and online techniques to quantify cross machine uniformity at both the input and output of the card. At the card input, uniformity is taken as representing both mass and openness characteristics of the feed matt. While at the card output, there are many available techniques that allow the on-line measurement of the mass uniformity of the carded web, determination of uniformity at the input level is more difficult. The approach that was taken was to use an off-line technique to find the mass and openness of the feed matt at different locations across the card. While traditionally mass as a property has been given a lot of importance, much less attention has been given to the concept of openness. This is due in part to the difficulty in quantifying openness. Openness is believed to have great significance in determining the overall quality of the carded web, especially with regard to the formation of neps. In order to make the concept of openness more clear, it was found necessary to develop a way of quantifying it. This was done by performing a compression test on the feed matt, and then fitting the compression data with an exponential curve. The coefficient of the exponent was used to represent openness. This approach was used to find the effect of the feed roller (pin type) on cross machine uniformity. It was found that the squeezing of the feed roller did not have an effect in redistributing the mass of the feed matt, but did have an effect in changing the openness of the feed matt. Because of the difficulty involved in the handling of the feed matt, a newly developed technique is suggested to characterize openness. While this method still relies on the compression characteristics of the feed matt, it is more appropriate because it is performed on-line. Preliminary results are reported. It was found that thickness measurement under carefully selected pressure value could be used to characterize openness precisely.

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